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Calcium Regulation of Cyclic Nucleotide Signaling in Lobster Olfactory Receptor Neurons
Author(s) -
Reich Gerhard,
Boekhoff Ingrid,
Breer Heinz,
Ache Barry W.
Publication year - 1999
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1999.0730147.x
Subject(s) - adenylyl cyclase , forskolin , olfactory receptor , biology , olfactory system , cyclic nucleotide gated ion channel , inositol trisphosphate , receptor , phosphodiesterase , calcium , signal transduction , cyclic nucleotide , olfactory receptor cell , microbiology and biotechnology , medicine , chemistry , biochemistry , inositol , nucleotide , neuroscience , enzyme , gene
An elevated free Ca 2+ concentration reduces odor‐stimulated production of cyclic AMP (cAMP) in the outer dendritic membranes of lobster olfactory receptor neurons in vitro. This effect can occur within 50 ms of odor stimulation. The effect is concentration‐dependent at submicromolar concentrations of free Ca 2+ . An elevated free Ca 2+ concentration also reduces basal and forskolin‐stimulated cAMP levels in a concentration‐dependent manner, suggesting that Ca 2+ is not targeting the activation of the odor receptor/G protein complex. The degradation of synthetic cAMP by phosphodiesterases is not enhanced by an increased free Ca 2+ concentration, suggesting that Ca 2+ acts by down‐regulating the olfactory adenylyl cyclase. Western blot analysis of the lobster olfactory sensilla that contain the outer dendrites reveals a protein in the transduction zone with a molecular mass of ∼ 138 kDa that is immunoreactive to an antiserum against adenylyl cyclase type III. Given earlier evidence that Ca 2+ potentially enters the receptor cell through odor‐activated inositol 1,4,5‐trisphosphate‐gated channels, our results suggest a possible route for cross talk between the cyclic nucleotide and the inositol phospholipid signaling pathways in lobster olfactory receptor neurons.